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Communications, IEEE Transactions on

Issue 4 • Date August 1972

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  • [Front cover and table of contents]

    Publication Year: 1972 , Page(s): 0
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    Freely Available from IEEE
  • Preface

    Publication Year: 1972 , Page(s): 687 - 688
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    Freely Available from IEEE
  • [Back cover]

    Publication Year: 1972 , Page(s): 0
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    Freely Available from IEEE
  • Matched-Transmission Technique for Channels With Intersymbol Interference

    Publication Year: 1972 , Page(s): 774 - 780
    Cited by:  Papers (297)  |  Patents (75)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (616 KB)  

    A new transmission scheme for channels with intersymbol interference named "matched-transmission (MT) technique" is proposed. An implementation of the MT system is presented and its relations with conventional techniques are described. It is shown that the partial response scheme is a special case of our new technique. The performance of the MT technique is discussed from the view point of the output signal-to-noise ratio and the system is shown to attain asymptotically the bound performance predicted by the information theory. View full abstract»

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  • An Optical Communication System Using Envelope Modulation

    Publication Year: 1972 , Page(s): 813 - 819
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (704 KB)  

    A wide-band optical communication system that modulates the envelope of the carrier of a high-speed optical pulse having no relation to the PCM signals, was developed. This optical pulse is supplied from a He-Ne gas laser oscillator that is controlled to generate a single transversal mode. The transmission bit rate of this optical communication system is 123 Mbits/s, and this system has a transmission capacity of three monochrome video signals, three program signals, and one channel of 48-kHz high-speed facsimile signal or one National Television System Commission (NTSC) color TV signal and one program signal. When this optical communication system is used to propagate through the atmosphere for a distance of 2-3 km, reliability is expected to be 99 percent. View full abstract»

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  • Synchronization for Unknown Signal Sequence by Learning Procedure

    Publication Year: 1972 , Page(s): 780 - 787
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (696 KB)  

    Methods of synchronization for an unknown signal sequence by learning procedure, which computes a posteriori probabilities for the signal location, are presented. First, to avoid the difficulties of the interference between successive intervals, a signal sequence with ample guard spaces for getting rid of the interference is treated. Next, the case without guard space is treated. To the nonsupervised case, some methods are applied. The methods proposed in this paper have a form of double learning with respect to the unknown signal form and the signal location. Also some results of computer simulation are presented. View full abstract»

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  • Queueing-Delay Formula for Common-Channel Signaling Systems

    Publication Year: 1972 , Page(s): 787 - 791
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    An approximate queueing model for common-channel signaling systems has been developed and the queueing-delay distribution has been obtained. As a special case, the approximate average queueing-delay formula for common-channel signaling systems has been derived. By simulation, it has been ascertained that this formula is reasonably accurate. View full abstract»

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  • Time-Division Switching Networks With Partial-Access Pulse Shifters Performing Serial-Parallel Conversion

    Publication Year: 1972 , Page(s): 762 - 768
    Cited by:  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (712 KB)  

    Some means of time-slot interchanging is required in a pulse-code-modulation (PCM) transit switching system to satisfy the blocking requirements due to the fact that average trunk loading is high and that the time slots of incoming calls are preassigned at the remote office. This paper presents the use of serial-to-parallel conversion and parallel-to-serial conversion pulse shifters, both having limited time-slot interchange capability at the input and the output of the switching networks, respectively. The features of the system are that the required memory capacity is much smaller than the conventional systems and that serial transmission and parallel switching are possible. The results of optimization through blocking probability evaluation and network cost estimation are also described for networks with one, two, and three gate stages, and with an additional parallel pulse-shifter stage. View full abstract»

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  • Development of a Small-Size Telephone Set Using Integrated Circuits

    Publication Year: 1972 , Page(s): 830 - 834
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    A small-size telephone set under developmental research at Nippon Telegraph and Telephone Public Corporation (NTT) is presented. The telephone utilizes recent advances in integrated-circuit technology and miniaturization technology of telephone parts, and offers several additional new services and human engineering improvements in size, weight, and comfort. View full abstract»

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  • Carrier Synchronizer for Coherent Detection of High-Speed Four-Phase-Shift-Keyed Signals

    Publication Year: 1972 , Page(s): 803 - 808
    Cited by:  Papers (9)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (592 KB)  

    In a high-speed digital radio relay system with four-phase-shift keying and coherent detection, it is very important to realize an accurate, stable, and wide-band carrier synchronizer. In this paper, the influence of time delay causing trouble for the wide-band synchronizer realization is analyzed. Then the design procedure of this synchronizer is described. Finally, the realizability of such a synchronizer is proved by the experimental results at a 1.7-GHz intermediate frequency and a 200-MHz clock frequency. View full abstract»

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  • Large-Capacity Magnetic-Drum Memory System for an Electronic Switching System

    Publication Year: 1972 , Page(s): 768 - 774
    Cited by:  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (760 KB)  

    A stored program-controlled electronic switching system (ESS) requires a large-capacity memory to store various kinds of programs and data. This paper describes a hierarchy arrangement including a high-speed memory and a low-cost largecapacity magnetic-drum memory for reduction of the cost of the ESS. The paper also describes the design philosophy, reliability, structure, and evaluation of the system. A magnetic drum with hydrodynamic floating heads (memory capacity: 3.7 \times 10^{7} bits, clock rate: 2.2 MHz) was employed. The magnetic-drum memory system can provide transfer of individual words (each consisting of 41 bits), transfer of variable-length data by flag bit control, and content-addressable access. Furthermore, the system is designed to be most suitable for transfer of the large amount of data required by the switching system. The data throughput of the magnetic-drum memory system is 210 kbytes/s in a burst mode. The mean time between failures (MTBF) of the system is approximately 3.5 \times 10^{3} h. This system assures reliability required for the ESS and high performance for application of the ESS to stored data switching as well as telephone switching. View full abstract»

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  • Microwave and Millimeter-Wave Communications in Japan

    Publication Year: 1972 , Page(s): 717 - 725
    Cited by:  Papers (2)
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    This paper reviews the status of research and development in both microwave radio-relay systems and millimeter-wave transmission systems as well as the technical features in these fields, mainly developed under the auspices of Nippon Telegraph and Telephone Public Corporation (NTT). Recent activities have been the development of new solid-state devices and high-capacity systems. The application of solid-state techniques is being extended to systems of both analog and digital transmission, such as the 2700 multichannel telephone transmission system in frequency division multiplexing (FDM)-FM radio-relay system, an experimental 20-GHz PCM radio-relay system capable of 400 Mbits/s pulse transmission, and a guided millimeter-wave system of 800-Mbit/s transmission at 40-80 GHz. The microwave integrated circuit (MIC) is also becoming very important in utilizing these high-frequency regions, which should be a valuable resource in the future when a vast information transmission capability will be required. View full abstract»

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  • Characteristics of an Experimental Guided Millimeter-Wave Transmission System

    Publication Year: 1972 , Page(s): 808 - 813
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    An experimental guided millimeter-wave transmission system is constructed employing two 806-Mbit/s digital repeaters, an 8.4-km waveguide line loop, and channel coupling networks. This paper presents its characteristics, such as waveforms, amplitude and delay, error rate, and timing jitter in some detail. View full abstract»

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  • An Audio Response Unit Based on Partial Autocorrelation

    Publication Year: 1972 , Page(s): 792 - 797
    Cited by:  Papers (19)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (584 KB)  

    This paper describes an audio response unit used in data communication services. The speech segments necessary to respond are stored in a large capacity magnetic drum in terms of partial autocorrelation (PARCOR) coefficients and excitation source information. PARCOR coefficient is a new parameter to express accurately the spectrum envelope of speech signals. Multiple speech signals can be synthesized simultaneously by means of a timemultiplexed digital filter composed of a high-speed arithmetic unit. The unit is able to respond to more than 7000 speech segments of 1-s duration. View full abstract»

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  • Electronic Switching Systems in Japan

    Publication Year: 1972 , Page(s): 746 - 752
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    A recently introduced large-size commercially available electronic switching system has versatility in application to different hierarchies of switching stages and is available not only in the telephone systems, but for forthcoming new telecommunication services such as video telecommunications, data applications, mobile radio telephones, etc. Successive developmental programs are now in progress for remote control switching systems, a small-medium-size electronic switching system and data-switching systems. In the international telecommunication field, an electronic telegraph switching system has been completed and electronic telex and telephone switching systems and a data-switching system are now under development. This paper describes some features of various electronic switching systems available in Japan for domestic and international telecommunications. View full abstract»

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  • Cable Communications in Japan

    Publication Year: 1972 , Page(s): 707 - 717
    Cited by:  Papers (1)
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    Japanese coaxial toll systems at the end of the fiscal year 1970 had grown to 29 980 km of coaxial cable (including both tubes of two-tube systems). In the next seven years, 1971 to 1977, the requirement is expected to be three times this capacity. Cable transmission systems fully utilizing modem electronics and communication engineering techniques are being developed to best meet this expected growth and to provide new wider band services. View full abstract»

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  • TTT System (50 Mbits/s PCM-TDMA System With Time Preassignment and TASI) and Its Satellite Test Results

    Publication Year: 1972 , Page(s): 820 - 825
    Cited by:  Papers (1)  |  Patents (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (664 KB)  

    An experimental 50 Mbits/s pulse-code modulation-time-division multiple access (PCM-TDMA) system with time preassignment and time-assignment speech interpolation (TASI) features (called the TTT system) was built for use in a satellite test. This system was designed for application in the INTELSAT IV network and has the channel capacity of more than 700 telephone channels. This capacity can be increased up to twice when pulse-code modulation-time-assignment speech interpolation (PCM-TASI) is adopted. The field test was conducted via INTELSAT III in 1970 and satisfactory results were obtained, which encourages the introduction of the TDMA system for commercial use. View full abstract»

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  • Mobile Radio Communications in Japan

    Publication Year: 1972 , Page(s): 738 - 746
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (920 KB)  

    After a short historical sketch of mobile communications in Japan, technical problems and future prospects are described. The peculiarities characteristic of mobile communication include complicated radio propagation and requirements for continuous communication and determination of mobile subscribers' location. This paper discusses major problems of future mobile communication, for example, radio propagation, controlling, and switching and radio equipment involved in meeting the future demands of a large number of subscribers over widespread service areas. Effective use of an electronic switching system will enable the mobile communication network to be integrated with existing fixed communication networks. View full abstract»

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  • Data Communications in Japan

    Publication Year: 1972 , Page(s): 753 - 762
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    Aspects of data communications in Japan are broadly summarized in this paper. First, various networks for data communication are described and some examples of data communication services using these networks are mentioned. Next, some topics in data communication technology are outlined. Topics include two large-scale computer projects and R&D on pattern recognition techniques in the data-processing field, standard modems now in use and new modems for PCM transmission and other uses in the data transmission field, optical character readers (OCR) and an audio-response unit, as well as various printers in the data terminal equipment field. View full abstract»

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  • Satellite Communications in Japan

    Publication Year: 1972 , Page(s): 730 - 737
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (928 KB)  

    This paper describes recent research and development of satellite communication technology in Japan together with the future prospects. Newly developed earth station facilities for both commercial and experimental purposes are described first. New satellite communication systems, such as STAR, SMAX, TTT, SSB-PM, and SSRA, which originated and/or have been studied extensively in Japan, are described briefly. Recent developments of microwave and millimeter-wave antennas, parametric amplifiers, high-power tubes, etc., are surveyed. Brief descriptions are also given of radio-wave propagation studies and development plans for Japanese communication satellites. View full abstract»

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  • Recent Progress in Communication Theory in Japan

    Publication Year: 1972 , Page(s): 696 - 707
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    This paper reviews recent progress in communication theory in Japan, mainly in the past three years. The topics to be discussed include 1) waveform transmission in band-limited channels and active transmission lines, 2) source-coding problems such as optimal quantizing characteristics, delta modulation, and linear transformation, 3) transmission codes, where mainly multilevel codes have been discussed, 4) new information transmission and modulation schemes, and 5) theories of traffic and switchingsystem design. View full abstract»

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  • Optical Communications in Japan

    Publication Year: 1972 , Page(s): 725 - 730
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (712 KB)  

    This paper reviews research and developmental activities in optical communications currently under way in Japan. Three major systems: 1) atmospheric optical communication systems, 2) optical-cable systems, and 3) lens-waveguide systems, using various types of lasers and newly developed optical devices and components, have been extensively studied at the Electrical Communication Laboratories of Nippon Telegraph and Telephone (NTT) and other electronic manufacturing companies in Japan. View full abstract»

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  • New Alphagraphic Printer GRAPHTYPER

    Publication Year: 1972 , Page(s): 797 - 802
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    This paper describes a new teleprinter that can print graphs as well as characters through the combination of an X-Y plotter using a high-speed incremental servo with a large-scale integration (LSI) character pattern memory that converts telegraphic signals into plotter signals. This device prints 20 characters per second, and the characters are formed by connecting segment vectors in eight different directions with one stroke. Design criteria of the incremental drive system and the selection of the symbol font are also described. View full abstract»

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  • General Trend in Electrical Communications in Japan

    Publication Year: 1972 , Page(s): 689 - 696
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    Systems are currently being designed for higher reliability and greater economy. Larger transmission capacity is required to meet a rapid increase in recent communication demands instigated by the introduction of video and information communications facilities. More flexibility, to deal with the variety of communication modes to come, and smaller hardware dimensions, to overcome situations caused by the high population density, seem to be particularly sought in the communication technology of Japan. Research and development concentrate on these objectives. The following is an explanation of the present state of the art and general trends in this country. View full abstract»

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  • Construction of Highly Accurate Segment Companding Voice Codec

    Publication Year: 1972 , Page(s): 825 - 829
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (496 KB)  

    Construction of a highly accurate segment companding voice codec is described in this paper. It is shown that an ideal precompressor placed in front of the segment coder enables moderating the accuracy required by 4 times in the 13-segment coder and by 8 times in the 15-segment coder. Two precompressor circuits with a negligible accuracy degradation are proposed and their performances are thoroughly discussed. It is shown that highly accurate sequential feedback segment companding coders, such as the 8-bit 13- or 15-segment coder, can be realized easily with these precompressors. View full abstract»

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Aims & Scope

IEEE Transactions on Communications focuses on all telecommunications including telephone, telegraphy, facsimile, and point-to-point television by electromagnetic propagation.

 

 

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Meet Our Editors

Editor-in-Chief
Robert Schober
University of British Columbia